Hong Kong Exchanges and Clearing and the Shanghai Stock Exchange signed an agreement yesterday to exchange real-time stock prices for the 48 mainland companies listed on both markets. Under the agreement, effective from January 1, the exchanges can redistribute each other's basic real-time market data for the companies with dual listings to their own authorised information vendors. Fees for exchanging data will be waived. 'The agreement will increase the transparency of the mainland and Hong Kong markets and enhance the two exchanges' market data service quality,' said Shanghai Stock Exchange general manager Zhang Yujun. Dual-listed shares account for 29 per cent of HKEx's turnover. HKEx was also in talks with Shenzhen Stock Exchange on similar co-operation for the eight mainland companies that were dual-listed in Hong Kong and Shenzhen, said HKEx chief executive Paul Chow Man-yiu. HKEx planned to provide free stock quotes to some websites next year, Mr Chow said. Thirty-four companies showed interest in joining the tender for developing the distribution model, he said. HKEx now provides stock prices on its website with a 15-minute lag.